The votes, in the Senate and lower house, came in a highly charged atmosphere. Some protestors clashed violently with the police, who fired tear gas, as tens of thousands of people marched through Rome calling on Mr. Berlusconi to step down. The government called in 1,500 police officers to keep order.
On Tuesday, the man who brought personality-driven politics to a nation once known for its revolving-door governments once again proved that his personal fate was inexorably entwined with that of his country's.
In spite of the victory, both were plunged into political uncertainty on Tuesday. Although his mandate is set to end in 2013, Mr. Berlusconi, with a razor-thin majority, no longer has the margin to govern, and analysts predicted that he might resign in the coming weeks and call early elections anyway.
Mr. Berlusconi's chief problems are within his own coalition. After the vote, Gianfranco Fini, a former ally who split with Mr. Berlusconi in July and voted against him on Tuesday, acknowledged his group's defeat. But he added that, "It will be clear in a few weeks that Berlusconi can't say he has won in political terms." Early elections could come at a high cost at a time when international markets are intensely focused on Italy's high debt and low growth.
While political chaos is nothing new to Italy, this time around the stakes are far higher since markets are intensely focused on Italy's high debt and slow growth.
Until recently, Tuesday's outcome would have been unthinkable in Italy, where Mr. Berlusconi has had an unshakeable grip on the country's politics for the better part of the past 15 years and its news media for even longer. Starting in the mid-1980s, his private television empire helped shape the public imagination.
"If I had said two years ago that in a couple of years Berlusconi would be looking for two or three votes for this government to survive, they'd have thought that I was crazy," said Paul Ginsborg, a historian at the University of Florence whose books include "Silvio Berlusconi: Television, Power and Patrimony."
He added that with Mr. Berlusconi's win, "the crisis is only postponed, not eliminated," since "he doesn't have a stable majority."
Mr. Berlusconi won by three votes in the lower house, with 314 in favor, 311 against and 2 abstentions. He also won a confidence motion in the Senate.
But he still lacks a clear parliamentary majority. Not even Mr. Berlusconi was strong - or focused enough - to hold together a fragile and ideologically incoherent center-right coalition that began unraveling after he split with a Mr. Fini, thereby losing his parliamentary majority.
Mr. Fini, a former neo-fascist turned moderate who is also the speaker of the lower house, accused Mr. Berlusconi of being undemocratic and formed a breakaway grouping called Future and Liberty for Italy. Last month, Mr. Fini withdrew four cabinet members, formalizing the crisis.
Mr. Fini's grouping had enough power to help bring down Mr. Berlusconi. But in spite of his statesmanlike demeanor and growing consensus, Mr. Fini still does not have enough power to succeed Mr. Berlusconi.
Indeed, Mr. Fini appeared to be the biggest loser in Tuesday's election, the challenger who ultimately wasn't up to the challenge.
Critics accused Mr. Berlusconi of squandering his majority and focusing more on his personal life - not only the now-infamous wild parties, but also his many legal sagas - than on the country's problems.
In January, Italy's Constitutional Court is set to vote on whether a law passed by Mr. Berlusconi's government granting him and the nation's top office holders immunity from prosecution violates the Constitutional principle that all citizens are equal before the law.
Over the weekend, Mr. Fini said in a television interview that Mr. Berlusconi only wanted to stay in power to avoid prosecution.
Ahead of Tuesday's vote, a leading opposition politician called on judges to investigate whether there was evidence that Mr. Berlusconi had bought some undecided parliamentarians. Italian papers have been filled with unconfirmed reports that Mr. Berlusconi had offered jobs and even mortgage payments in exchange for support.
In a final appeal to Parliament on Monday, Mr. Berlusconi had said it would be "folly" to bring down the government amid the economic crisis.
Economists say Italy needs significant structural reform and cost cutting in order to stimulate growth and reduce its debt, which at 118 percent of gross domestic product is the second-highest in the 16-member Euro zone after Greece.
Yet more than any roadblocks imposed by the center-left opposition, Mr. Berlusconi's difficulty in imposing reform lies within his own center-right coalition, an amalgam of the powerful Northern League, which is fighting to keep tax revenue local, and Southern politicians from a more jobs-for-votes tradition.
If Italy does go to early elections this spring, the Northern League is expected to register significant gains. Their point-man in the government is the well-respected finance minister, Giulio Tremonti, and in one scenario he might become prime minister.
Gaia Pianigiani contributed reporting from Rome.